Carnitine Palmitoyltransferase System: A New Target for Anti-Inflammatory and Anticancer Therapy?

Leptin decreases Th17/Treg ratio to facilitate neuroblastoma via inhibiting long-chain fatty acid catabolism in tumor cells

The exploration of therapeutic targets in neuroblastoma (NB), which needs more attempts, can benefit patients with high-risk NB. Based on metabolomic and transcriptomic data in mediastinal NB tissues, we found that the content of long-chain acylcarnitine (LCAC) was increased and positively associated with leptin expression in advanced NB. Leptin over-expression forced naïve CD4+ T cells to differentiate into Treg cells instead of Th17 cells, which benefited from NB cell proliferation, migration, and drug resistance. Mechanically, leptin in NB cells blunted the activity of carnitine palmitoyltransferase 2 (CPT2), the key enzyme for LCAC catabolism, by inhibiting sirtuin 3-mediated CPT2 deacetylation, which depresses oxidative phosphorylation (OXPHOS) for energy supply and increases lactic acid (LA) production from glycolysis to modulate CD4+ T cell differentiation. These findings highlight that excess leptin contributes to lipid metabolism dysfunction in NB cells and subsequently misdirects CD4+ T cell differentiation in tumor micro-environment (TME), indicating that targeting leptin could be a therapeutic strategy for retarding NB progression.

Unveiling the immunological terrain of pancreatic ductal adenocarcinoma: strategies to prompt immunotherapy from Mendelian randomization

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is challenging to treat due to its immunosuppressive tumor microenvironment (TME) and resistance to immune checkpoint inhibitors. This study aims to discover new therapeutic targets and predictive biomarkers for PDAC.

METHODS

Using Mendelian randomization, we studied causal relationships between PDAC and an array of immune cell traits, bacterial traits, inflammatory factors, and blood metabolites. We employed large genome-wide association study datasets and the two-sample MR approach for the investigation.

RESULTS

Our results highlight suggestive evidence of associations between PDAC and distinct immune cell phenotypes, revealing nuanced alterations across monocytes, T-cells, B-cells, dendritic cells, and myeloid-derived suppressor cells. Our study provides a granular view of the PDAC-immune interface, identifying key immune cell traits and their associations with PDAC. For instance, our findings suggest a detrimental reduction in various monocyte traits, alongside a decrease in B-cell populations. Conversely, certain T-cell subsets showed increased associations, indicating potential targets for immunotherapeutic strategies. The bacterial trait associations, particularly with Collinsella and Ruminococcus torques, highlight the gut microbiome's influence on immune modulation and PDAC pathogenesis. Additionally, the traits concerning Interleukin-12 subunit beta levels and T-cell surface glycoprotein CD5 levels further indicate their function of this complex interaction.

CONCLUSIONS

This study enhances our understanding of PDAC's resistance to immunotherapies and highlights the potential of personalized immunotherapy and metabolic pathway modulation in PDAC treatment. Our findings provide supportive evidence for research and clinical translation.

The role of adipogenic niche resident cells in colorectal cancer progression in relation to obesity

Colorectal cancer (CRC) is the third most common cancer worldwide and has one of the highest mortality rates. Considering its nonlinear etiology, many risk factors are associated with CRC formation and development, with obesity at the forefront. Obesity is regarded as one of the key environmental risk determinants for the pathogenesis of CRC. Excessive food intake and a sedentary lifestyle, together with genetic predispositions, lead to the overgrowth of adipose tissue along with a disruption in the number and function of its building cells. Adipose tissue-resident cells may constitute part of the CRC microenvironment. Alterations in their physiology and secretory profiles observed in obesity may further contribute to CRC progression, and despite similar localization, their contributions are not equivalent. They can interact with CRC cells, either directly or indirectly, influencing various processes that contribute to tumorigenesis. The main aim of this review is to provide insights into the diversity of adipose tissue resident cells, namely, adipocytes, adipose stromal cells, and immunological cells, regarding the role of particular cell types in co-forming the CRC microenvironment. The scope of this study was also devoted to the abnormalities in adipose tissue physiology observed in obesity states and their impact on CRC development.

Rational Design, Synthesis, and In Vitro Activity of Heterocyclic Gamma-Butyrobetaines as Potential Carnitine Acetyltransferase Inhibitors

This study investigates heterocyclic gamma-butyrobetaine (GBB) analogs as metabolic modulators through an integrated approach involving rational design, molecular docking, synthesis, and in vitro evaluation. The compounds synthesized demonstrated promising inhibitory potential toward carnitine acetyltransferase (CAT) and presumably other enzymes within the carnitine transferase family, with IC50 values ranging from 2.24 to 43.6 mM. Notably, some compounds demonstrated superior activity to the reference drug Meldonium (IC50 = 11.39 mM). A substantial outcome of the study that might serve as a foundation for future optimization and synthesis of more potent compounds was that a bulky, hydrophobic substituent at the gamma position enhances inhibitory activity, whereas esterification and increased polarity diminish it. The most effective compound was determined to be a reversible competitive inhibitor of CAT, with a Ki value of 3.5 mM comparable to Meldonium's Ki of 1.63 mM. These results suggest that heterocyclic GBB analogs present potential candidates for regulating metabolic processes and treating conditions including ischemic diseases, diabetes, and specific cancers.

Carnitine O-Acetyltransferase as a Central Player in Lipid and Branched-Chain Amino Acid Metabolism, Epigenetics, Cell Plasticity, and Organelle Function

Carnitine O-acetyltransferase (CRAT) is a key mitochondrial enzyme involved in maintaining metabolic homeostasis by mediating the reversible transfer of acetyl groups between acetyl-CoA and carnitine. This enzymatic activity ensures the optimal functioning of mitochondrial carbon flux by preventing acetyl-CoA accumulation, buffering metabolic flexibility, and regulating the balance between fatty acid and glucose oxidation. CRAT's interplay with the mitochondrial carnitine shuttle, involving carnitine palmitoyltransferases (CPT1 and CPT2) and the carnitine carrier (SLC25A20), underscores its critical role in energy metabolism. Emerging evidence highlights the structural and functional diversity of CRAT and structurally related acetyltransferases across cellular compartments, illustrating their coordinated role in lipid metabolism, amino acid catabolism, and mitochondrial bioenergetics. Moreover, the structural insights into CRAT have paved the way for understanding its regulation and identifying potential modulators with therapeutic applications for diseases such as diabetes, mitochondrial disorders, and cancer. This review examines CRAT's structural and functional aspects, its relationships with carnitine shuttle members and other carnitine acyltransferases, and its broader role in metabolic health and disease. The potential for targeting CRAT and its associated pathways offers promising avenues for therapeutic interventions aimed at restoring metabolic equilibrium and addressing metabolic dysfunction in disease states.

Critical review on the intervention effects of flavonoids from cereal grains and food legumes on lipid metabolism

Obesity, often caused by disorders of lipid metabolism, is a global health concern. Flavonoids from staple grains and legumes are expected as a safer and more cost-effective alternative for the future development of dietary flavonoid-based anti-obesity dietary supplements or drugs. This review systematically summarized their content variation, metabolism in the human body, effects and molecular mechanisms on lipid metabolism. These flavonoids intervene in lipid metabolism by inhibiting lipogenesis, promoting lipolysis, enhancing energy metabolism, reducing appetite, suppressing inflammation, enhancing insulin sensitivity, and improving the composition of the gut microbial. Fermentation and sprouting techniques enhance flavonoid content and these beneficial effects. The multidirectional intervention of lipid metabolism is mainly through regulating AMPK signaling pathway. This study provides potential improvement for challenges of application, including addressing high extraction costs and improving bioavailability, ensuring safety, filling clinical study gaps, and investigating potential synergistic effects between flavonoids in grains and legumes, and other components.

Alcohol promotes CPT1A-induced lipid metabolism disorder to sentinel-regulate acute pancreatitis

BACKGROUND AND AIMS

Previous studies have confirmed that alcohol can increase the sensitivity of the pancreas to stressors and exacerbate the severity of pancreatitis when excessive alcohol intake is combined with other causes. In the current work, this study attempted to explore how does alcohol regulate cerulein-induced acute pancreatitis, especially before inflammation occurs.

METHODS

Proteomics was performed to analyze the differentially expressed proteins in pancreatic tissues from a rat model of pancreatitis. The metabolite levels in the pancreatic tissue, serum of rats and serum of persons with a history of alcohol consumption were detected by LC‒MS/MS. In the present study the impact of etomoxir (a carnitine palmitoyl-transferase 1A-specific inhibitor) treatment on AR42J cells treated with alcohol and the effect of etomoxir injection on the inflammatory response in an alcohol + cerulein-induced AAP rat model was evaluated.

RESULTS

When treated with the same amount of cerulein, the rats that ingested alcohol presented with more severe pancreatitis. The proteomics results revealed that the fatty acid degradation pathway was closely related to the development of alcoholic acute pancreatitis, and CPT1A exhibited the greatest increase (approximately twofold increase). The products (acylcarnitines) of CPT1A were changed in the serum of persons with a history of alcohol consumption. Etomoxir treatment mitigates the influence of alcohol stimulation on the aberrant expression of proteins associated with oxidative stress, increased ROS production, mitochondrial ultrastructural alterations and mitochondrial dysfunction in AR42J cells. Etomoxir injection reduced the inflammatory response in the AAP rat model.

CONCLUSION

Alcohol upregulates CPT1A protein expression in pancreatic tissue, resulting in abnormal lipid metabolism. The products of lipid metabolism, ROS, contribute to mitochondrial ultrastructural alterations and mitochondrial dysfunction. These changes act as sentinel events that regulate acute pancreatitis.

A Collection of Novel Antitumor Agents That Regulate Lipid Metabolism in the Tumor Microenvironment

Lipid metabolism disorder is the cause of one of the most significant metabolic changes in tumors. In the process of tumor occurrence and development, tumor cells choose a continuous metabolic adaptation to accommodate the changing environment to the maximum extent possible. In a variety of tumors, the uptake, production, and storage of lipids are generally upregulated. Tumor cells take advantage of lipid metabolism to access basic energy, biofilm components, and signal molecules of the tumor microenvironment required for proliferation, survival, invasion, and metastasis. This Perspective briefly uncovers the main metabolic processes and key factors involved in lipid metabolism reprogramming, mainly related to lipid uptake, de novo synthesis and storage of fatty acids, oxidation of fatty acids, cholesterol synthesis, and related regulatory factors. From a medicinal chemistry perspective, agents against related key targets are reviewed, expecting to pave the way for promising antitumor drugs with prospects for application through lipid metabolism reprogramming.

Metabolic Reprogramming in Cancer: Implications for Immunosuppressive Microenvironment

Cancer is a complex and heterogeneous disease characterised by uncontrolled cell growth and proliferation. One hallmark of cancer cells is their ability to undergo metabolic reprogramming, which allows them to sustain their rapid growth and survival. This metabolic reprogramming creates an immunosuppressive microenvironment that facilitates tumour progression and evasion of the immune system. In this article, we review the mechanisms underlying metabolic reprogramming in cancer cells and discuss how these metabolic alterations contribute to the establishment of an immunosuppressive microenvironment. We also explore potential therapeutic strategies targeting metabolic vulnerabilities in cancer cells to enhance immune-mediated anti-tumour responses. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02044861, NCT03163667, NCT04265534, NCT02071927, NCT02903914, NCT03314935, NCT03361228, NCT03048500, NCT03311308, NCT03800602, NCT04414540, NCT02771626, NCT03994744, NCT03229278, NCT04899921.

Repeated Injection of Xylazine Causes Liver Injury Through the PPAR Signaling Pathway in Rats

With the gradual emergence of xylazine as a street drug, incidents of xylazine poisoning are now occurring worldwide. However, it remains unknown whether long-term exposure to xylazine causes nonalcoholic fatty liver disease (NAFLD). In the present study, the rats were injected with xylazine intraperitoneally for 28 consecutive days, and then serum and liver tissues were collected for analysis. Weight loss was observed in the 40 mg/kg group and elevated levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were observed. Histopathologic examination showed hepatic steatosis, necrosis, and fibrosis. By mRNA sequencing, 192 upregulated genes and 277 downregulated genes were found in the 40 mg/kg group, and the PPAR signaling pathway was ranked first in the KEGG pathway analysis. Four genes in the PPAR signaling pathway, Fabp5, Acox2, and Cpt2, were also verified in the 40 mg/kg group by RT-qPCR analysis and western blot. Our results demonstrated that long-term injection of xylazine causes NAFLD and the PPAR signaling pathway plays a core role in the process of xylazine-associated liver injury.

From Adipose to Ailing Kidneys: The Role of Lipid Metabolism in Obesity-Related Chronic Kidney Disease

Obesity has emerged as a significant public health crisis, closely linked to the pathogenesis and progression of chronic kidney disease (CKD). This review explores the intricate relationship between obesity-induced lipid metabolism disorders and renal health. We discuss how excessive free fatty acids (FFAs) lead to lipid accumulation in renal tissues, resulting in cellular lipotoxicity, oxidative stress, and inflammation, ultimately contributing to renal injury. Key molecular mechanisms, including the roles of transcriptional regulators like PPARs and SREBP-1, are examined for their implications in lipid metabolism dysregulation. The review also highlights the impact of glomerular and tubular lipid overload on kidney pathology, emphasizing the roles of podocytes and tubular cells in maintaining kidney function. Various therapeutic strategies targeting lipid metabolism, including pharmacological agents such as statins and SGLT2 inhibitors, as well as lifestyle modifications, are discussed for their potential to mitigate CKD progression in obese individuals. Future research directions are suggested to better understand the mechanisms linking lipid metabolism to kidney disease and to develop personalized therapeutic approaches. Ultimately, addressing obesity-related lipid metabolism disorders may enhance kidney health and improve outcomes for individuals suffering from CKD.

SREBP1 induction mediates long-term statins therapy related myocardial lipid peroxidation and lipid deposition in TIIDM mice

Statins therapy is efficacious in diminishing the risk of major cardiovascular events in diabetic patients. However, our research has uncovered a correlation between the prolonged administration of statins and an elevated risk of myocardial dysfunction in patients with type II diabetes mellitus (TIIDM). Here, we report the induction of sterol regulatory element-binding protein 1 (SREBP1) activation, associated lipid peroxidation, and the consequent diabetic myocardial dysfunction after statin treatment and explored the underlying mechanisms. In db/db mice, we observed that 40 weeks atorvastatin (5 and 10 mg/kg) and rosuvastatin (20 mg/kg) administration exacerbated diabetic myocardial dysfunction by echocardiography and cardiomyocyte contractility assay, increased myocardial inflammation and fibrosis as shown by CD68, IL-1β, Masson's staining and Collagen1A1 immunohistochemistry (IHC) staining, increased respiratory exchange ratio (RER) by metabolic cage system assessment, exacerbated mitochondrial structural pathological changes by transmission electron microscopy (TEM) examination, increased deposition of lipid and glycogen by TEM, Oil-red and periodic acid-schiff stain (PAS) staining, which were corresponded with augmented levels of myocardial SREBP1 protein and lipid peroxidation marked by 4-hydroxynonenal (4-HNE) staining. Comparable myocardial fibrosis was also observed in KK-ay and low-dose streptozotocin (STZ)-induced TIIDM mice. Elevated SREBP1 levels were observed in the heart tissues from diabetic patients, which was positively correlated with their myocardial dysfunction. To elucidate the role of statin induced SREBP1 in lipid peroxidation and lipid deposition and related mechanism, we cultured neonatal mouse primary cardiomyocytes (NMPCs) and treated them with atorvastatin (10 μM, 24 h), tracing with [U-13C]-glucose and evaluating for SREBP1 expression and localization. We found that statin treatment elevated de novo lipogenesis (DNL) and the levels of SREBP1 cleavage-activating protein (SCAP), reduced the interaction of SCAP with insulin-induced gene 1 (Insig1), and enhance SCAP/SREBP1 translocation to the Golgi, which facilitate SREBP1 cleavage leading to its nuclear trans-localization and activation in NMPCs. Ultimately, SREBP1 knockdown or l-carnitine mitigated long-term statins therapy induced lipid peroxidation and myocardial fibrosis in low-dose STZ treated SREBP1+/- mice and l-carnitine treated db/db mice. In conclusion, we demonstrated that statin therapy may augment DNL by activating SREBP1, resulting in myocardial lipid peroxidation and lipid deposition.

Lysophospholipid Supplementation in Broiler Breeders' Diet Benefits Offspring's Productive Performance, Blood Parameters, and Hepatic β-Oxidation Genes

The present study aimed to investigate whether supplementation of modified lysophospholipids (LPLs) in the diet of broiler breeders can benefit their offspring. A total of 264 49-week-old breeders (Ross 308) were allocated and fed based on a 2 × 2 factorial arrangement with two levels of dietary energy (normal energy = 2800 kcal/kg and low energy = 2760 kcal/kg) and two LPL levels (0 and 0.5 g/kg) for periods of 8 and 12 weeks. The offspring were assessed for growth performance, serum parameters, hepatic antioxidative capability, and expression of genes involved in liver β-oxidation at 7 days old. The LPL inclusion improved (p < 0.01) average body weight (ABW), average daily gain (ADG), and feed conversion ratio (FCR). The offspring of 61-week-old breeders fed with LPL exhibited reduced serum triglyceride levels (p < 0.01) but an increase in hepatic glutathione peroxidase (p < 0.05). The LPL increased (p < 0.001) the mRNA expression of the PGC-1α gene in the liver. Supplementing LPL in low-energy diets resulted in higher FABP1 gene expression (p < 0.05) in the intestine. In conclusion, LPL supplementation in the breeders' diet improved offspring performance by enhancing fatty acid absorption, hepatic indices, and the expression of genes involved in liver β-oxidation.

Key Disease-Related Genes and Immune Cell Infiltration Landscape in Inflammatory Bowel Disease: A Bioinformatics Investigation

Inflammatory Bowel Diseases (IBD), which encompass ulcerative colitis (UC) and Crohn's disease (CD), are characterized by chronic inflammation and tissue damage of the gastrointestinal tract. This study aimed to uncover novel disease-gene signatures, dysregulated pathways, and the immune cell infiltration landscape of inflamed tissues. Eight publicly available transcriptomic datasets, including inflamed and non-inflamed tissues from CD and UC patients were analyzed. Common differentially expressed genes (DEGs) were identified through meta-analysis, revealing 180 DEGs. DEGs were implicated in leukocyte transendothelial migration, PI3K-Akt, chemokine, NOD-like receptors, TNF signaling pathways, and pathways in cancer. Protein-protein interaction network and cluster analysis identified 14 central IBD players, which were validated using eight external datasets. Disease module construction using the NeDRex platform identified nine out of 14 disease-associated genes (CYBB, RAC2, GNAI2, ITGA4, CYBA, NCF4, CPT1A, NCF2, and PCK1). Immune infiltration profile assessment revealed a significantly higher degree of infiltration of neutrophils, activated dendritic cells, plasma cells, mast cells (resting/activated), B cells (memory/naïve), regulatory T cells, and M0 and M1 macrophages in inflamed IBD tissue. Collectively, this study identified the immune infiltration profile and nine disease-associated genes as potential modulators of IBD pathogenesis, offering insights into disease molecular mechanisms, and highlighting potential disease modulators and immune cell dynamics.

Dysfunction of the carnitine cycle in tumor progression

The carnitine cycle is responsible for the transport of cytoplasmic fatty acids to the mitochondria for subsequent β-oxidation to maintain intracellular energy homeostasis. Recent studies have identified abnormalities in the carnitine cycle in various types of tumors; these abnormalities include the altered expression levels of carnitine cycle-related metabolic enzymes and transport proteins. Dysfunction of the carnitine cycle has been shown to influence tumorigenesis and progression by altering intracellular oxidative and inflammatory status or regulating tumor metabolic flexibility. Many therapeutic strategies targeting the carnitine cycle are actively being explored to modify the dysfunction of the carnitine cycle in patients with malignant tumors; such approaches include carnitine cycle-related enzyme inhibitors and exogenous carnitine supplementation. Therefore, here, we review the studies of carnitine in tumors, aiming to scientifically illustrate the dysfunction of the carnitine cycle in tumor progression and provide new ideas for further research.

The Relevance of the Endothelium in Cardiopulmonary Disorders

The endothelium is a cell monolayer that lines vessels and separates tissues from blood flow. Endothelial cells (ECs) have a multitude of functions, including regulating blood flow and systemic perfusion through changes in vessel diameter. When an injury occurs, the endothelium is affected by altering its functions and structure, which leads to endothelial dysfunction, a characteristic of many vascular diseases. Understanding the role that the endothelium plays in pulmonary vascular and cardiopulmonary diseases, and exploring new therapeutic strategies is of utmost importance to advance clinically. Currently, there are several treatments able to improve patients' quality of life, however, none are effective nor curative. This review examines the critical role of the endothelium in the pulmonary vasculature, investigating the alterations that occur in ECs and their consequences for blood vessels and potential molecular targets to regulate its alterations. Additionally, we delve into promising non-pharmacological therapeutic strategies, such as exercise and diet. The significance of the endothelium in cardiopulmonary disorders is increasingly being recognized, making ECs a relevant target for novel therapies aimed at preserving their functional and structural integrity.

CPT1A-IL-10-mediated macrophage metabolic and phenotypic alterations ameliorate acute lung injury

BACKGROUND

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common acute respiratory failure due to diffuse pulmonary inflammation and oedema. Elaborate regulation of macrophage activation is essential for managing this inflammatory process and maintaining tissue homeostasis. In the past decades, metabolic reprogramming of macrophages has emerged as a predominant role in modulating their biology and function. Here, we observed reduced expression of carnitine palmitoyltransferase 1A (CPT1A), a key rate-limiting enzyme of fatty acid oxidation (FAO), in macrophages of lipopolysaccharide (LPS)-induced ALI mouse model. We assume that CPT1A and its regulated FAO is involved in the regulation of macrophage polarization, which could be positive regulated by interleukin-10 (IL-10).

METHODS

After nasal inhalation rIL-10 and/or LPS, wild type (WT), IL-10-/-, Cre-CPT1Afl/fl and Cre+CPT1Afl/fl mice were sacrificed to harvest bronchoalveolar lavage fluid, blood serum and lungs to examine cell infiltration, cytokine production, lung injury severity and IHC. Bone marrow-derived macrophages (BMDMs) were extracted from mice and stimulated by exogenous rIL-10 and/or LPS. The qRT-PCR, Seahorse XFe96 and FAO metabolite related kits were used to test the glycolysis and FAO level in BMDMs. Immunoblotting assay, confocal microscopy and fluorescence microplate were used to test macrophage polarization as well as mitochondrial structure and function damage.

RESULTS

In in vivo experiments, we found that mice lacking CPT1A or IL-10 produced an aggravate inflammatory response to LPS stimulation. However, the addition of rIL-10 could alleviate the pulmonary inflammation in mice effectively. IHC results showed that IL-10 expression in lung macrophage decreased dramatically in Cre+CPT1Afl/fl mice. The in vitro experiments showed Cre+CPT1Afl/fl and IL-10-/- BMDMs became more "glycolytic", but less "FAO" when subjected to external attacks. However, the supplementation of rIL-10 into macrophages showed reverse effect. CPT1A and IL-10 can drive the polarization of BMDM from M1 phenotype to M2 phenotype, and CPT1A-IL-10 axis is also involved in the process of maintaining mitochondrial homeostasis.

CONCLUSIONS

CPT1A modulated metabolic reprogramming and polarisation of macrophage under LPS stimulation. The protective effects of CPT1A may be partly attributed to the induction of IL-10/IL-10 receptor expression.

Changes in the Expression of Inflammatory Genes Induced by Chronic Exercise in the Adipose Tissue: Differences by Sex

The impact of obesity on adipose tissue function is well acknowledged, but the role of physical exercise in regulating inflammatory markers and gene expression in obese individuals remains uncertain. This study aims to investigate the effects of chronic exercise on inflammatory gene expression in adipose tissue and to explore sex differences in response to exercise. The study involved 29 obese participants (13 men, 16 women) aged 38 to 54 years with a mean BMI of 36.05 ± 4.99 kg/m2. Participants underwent an 8-week concurrent training program comprising three weekly sessions of ~60 min each. The sessions included joint mobility exercises, cardiovascular activation, and cardiorespiratory resistance exercises at medium to low intensity. A fine-needle aspiration biopsy of abdominal subcutaneous adipose tissue was performed for gene expression analysis using quantitative polymerase chain reaction (qPCR). The study demonstrated that chronic exercise modulates the expression of pro-inflammatory genes in subcutaneous adipose tissue, particularly ADIPOR2 (p = 0.028), leptin (p = 0.041), and IFNg (p = 0.040) (downregulated). Interestingly, regardless of sex, the exercise programs had an independent effect on pro-inflammatory genes. Overall, this study provides insight into the role of chronic exercise in modulating adipose tissue gene expression in obese individuals. Further research involving both sexes is recommended to tailor exercise interventions for better outcomes.

Enterolignans: from natural origins to cardiometabolic significance, including chemistry, dietary sources, bioavailability, and activity

The enterolignans, enterolactone and enterodiol, the main metabolites produced from plant lignans by the gut microbiota, have enhanced bioavailability and activity compared to their precursors, with beneficial effects on metabolic and cardiovascular health. Although extensively studied, the biosynthesis, cardiometabolic effects, and other therapeutic implications of mammalian lignans are still incompletely understood. The aim of this review is to provide a comprehensive overview of these phytoestrogen metabolites based on up-to-date information reported in studies from a wide range of disciplines. Established and novel synthetic strategies are described, as are the various lignan precursors, their dietary sources, and a proposed metabolic pathway for their conversion to enterolignans. The methodologies used for enterolignan analysis and the available data on pharmacokinetics and bioavailability are summarized and their cardiometabolic bioactivity is explored in detail. The special focus given to research on the health benefits of microbial-derived lignan metabolites underscores the critical role of lignan-rich diets in promoting cardiovascular health.

CPT1C-positive cancer-associated fibroblast facilitates immunosuppression through promoting IL-6-induced M2-like phenotype of macrophage

Cancer-associated fibroblasts (CAFs) exhibit remarkable phenotypic heterogeneity, with specific subsets implicated in immunosuppression in various malignancies. However, whether and how they attenuate anti-tumor immunity in gastric cancer (GC) remains elusive. CPT1C, a unique isoform of carnitine palmitoyltransferase pivotal in regulating fatty acid oxidation, is briefly indicated as a protumoral metabolic mediator in the tumor microenvironment (TME) of GC. In the present study, we initially identified specific subsets of fibroblasts exclusively overexpressing CPT1C, hereby termed them as CPT1C+CAFs. Subsequent findings indicated that CPT1C+CAFs fostered a stroma-enriched and immunosuppressive TME as they correlated with extracellular matrix-related molecular features and enrichment of both immunosuppressive subsets, especially M2-like macrophages, and multiple immune-related pathways. Next, we identified that CPT1C+CAFs promoted the M2-like phenotype of macrophage in vitro. Bioinformatic analyses unveiled the robust IL-6 signaling between CPT1C+CAFs and M2-like phenotype of macrophage and identified CPT1C+CAFs as the primary source of IL-6. Meanwhile, suppressing CPT1C expression in CAFs significantly decreased IL-6 secretion in vitro. Lastly, we demonstrated the association of CPT1C+CAFs with therapeutic resistance. Notably, GC patients with high CPT1C+CAFs infiltration responded poorly to immunotherapy in clinical cohort. Collectively, our data not only present the novel identification of CPT1C+CAFs as immunosuppressive subsets in TME of GC, but also reveal the underlying mechanism that CPT1C+CAFs impair tumor immunity by secreting IL-6 to induce the immunosuppressive M2-like phenotype of macrophage in GC.

Metabolic Adaptations and Functional Activity of Macrophages in Homeostasis and Inflammation

In recent years, the role of cellular metabolism in immunity has come into the focus of many studies. These processes form a basis for the maintenance of tissue integrity and homeostasis, as well as represent an integral part of the immune response, in particular, inflammation. Metabolic adaptations not only ensure energy supply for immune response, but also affect the functions of immune cells by controlling transcriptional and post-transcriptional programs. Studying the immune cell metabolism facilitates the search for new treatment approaches, especially for metabolic disorders. Macrophages, innate immune cells, are characterized by a high functional plasticity and play a key role in homeostasis and inflammation. Depending on the phenotype and origin, they can either perform various regulatory functions or promote inflammation state, thus exacerbating the pathological condition. Furthermore, their adaptations to the tissue-specific microenvironment influence the intensity and type of immune response. The review examines the effect of metabolic reprogramming in macrophages on the functional activity of these cells and their polarization. The role of immunometabolic adaptations of myeloid cells in tissue homeostasis and in various pathological processes in the context of inflammatory and metabolic diseases is specifically discussed. Finally, modulation of the macrophage metabolism-related mechanisms reviewed as a potential therapeutic approach.

Tumor markers for lipid metabolism-related genes: Based on small cell lung cancer and bronchial asthma dual analysis

Numerous studies have elucidated the intricate relationship between bronchial asthma and small cell lung cancer (SCLC), as well as the role lipid metabolism genes play in transitioning from bronchial asthma to SCLC. Despite this, the predictive power of single gene biomarkers remains insufficient and necessitates the development of more accurate prognostic models. In our study, we downloaded and preprocessed scRNA-seq of SCLC from the GEO database GSE164404 and severe asthma scRNA-seq from GSE145013 using the Seurat package. Using the MSigDB database and geneCard database, we selected lipid metabolism-related genes and performed scRNA-seq data analysis from the gene expression GEO database, aiming to uncover potential links between immune signaling pathways in bronchial asthma and SCLC. Our investigations yielded differentially expressed genes based on the scRNA-seq dataset related to lipid metabolism. We executed differential gene analysis, gene ontology, and Kyoto Encyclopedia of Genes and Genomes analyses. In-depth GSEA pathway activation analysis, crucial target gene predictions via protein-protein interactions, and key cluster gene evaluations for differential and diagnostic ROC values correlation analysis confirmed that key cluster genes are significant predictors for the progression of bronchial asthma to SCLC. To validate our findings, we performed wet laboratory experiments using real-time quantitative PCR to assess the expression of these relevant genes in SCLC cell lines. In conclusion, this research proposes a novel lipid metabolism-related gene marker that can offer comprehensive insights into the pathogenesis of bronchial asthma leading to SCLC. Although this study does not directly focus on senescence-associated molecular alterations, our findings in the lipid metabolism genes associated with inflammation and cancer progression offer valuable insights for further research targeting senescence-related changes in treating inflammatory diseases.

Subtherapeutic Kitasamycin Promoted Fat Accumulation in the Longissimus Dorsi Muscle in Growing-Finishing Pigs

Kitasamycin (KM), a broad-spectrum macrolide antibiotic, has implications for growth performance and residue in animals and humans. This study aimed to explore the effects of different KM doses on intramuscular fat accumulation, cecal microflora, and short-chain fatty acids (SCFAs) using a growing-finishing pig model. Forty-two pigs were divided into three groups: control, subtherapeutic KM (50 mg/kg, KM50), and therapeutic KM (200 mg/kg, KM200) diets over 8 weeks. KM50 led to increased back fat thickness, fat content in the longissimus dorsi muscle (LM), and elevated plasma total cholesterol (TC) levels (p < 0.05), supported by upregulated lipid synthesis gene expression (Acc1, Fas, Scd1) (p < 0.05) in the LM. KM50 altered cecal microflora, reducing Lactobacillus spp. and Bifidobacterium spp. abundance, while increasing SCFA concentrations (acetic acid, propionic acid, total SCFAs) (p < 0.05). KM200 had minimal effects on intestinal weight and density, with increased apparent digestibility of nutrients. These findings highlight the dose-dependent impact of KM on intramuscular fat deposition. Subtherapeutic KM induced ectopic fat deposition, emphasizing potential risks in disease treatment for humans and animals.

Cardiac cell senescence: molecular mechanisms, key proteins and therapeutic targets

Cardiac aging, particularly cardiac cell senescence, is a natural process that occurs as we age. Heart function gradually declines in old age, leading to continuous heart failure, even in people without a prior history of heart disease. To address this issue and improve cardiac cell function, it is crucial to investigate the molecular mechanisms underlying cardiac senescence. This review summarizes the main mechanisms and key proteins involved in cardiac cell senescence. This review further discusses the molecular modulators of cellular senescence in aging hearts. Furthermore, the discussion will encompass comprehensive descriptions of the key drugs, modes of action and potential targets for intervention in cardiac senescence. By offering a fresh perspective and comprehensive insights into the molecular mechanisms of cardiac senescence, this review seeks to provide a fresh perspective and important theoretical foundations for the development of drugs targeting this condition.

Glutathione-Responsive Organosilica Hybrid Nanosystems for Targeted Dual-Starvation Therapy in Luminal Breast Cancer

Starvation therapy is an innovative approach in cancer treatment aimed at depriving cancer cells of necessary resources by impeding tumor angiogenesis or blocking the energy supply. In addition to the commonly observed anaerobic glycolysis energy supply mode, adipocyte-rich tumor tissue triggers the fatty acid energy supply pathway, which fuels the proliferation and metastasis of cancer cells. To completely disrupt these dual-energy-supply pathways, we developed an exceptional nanoreactor. This nanoreactor consisted of yolk-shell mesoporous organosilica nanoparticles (YSMONs) loaded with a fatty acid transport inhibitor (Dox), conjugated with a luminal breast-cancer-specific targeting aptamer, and integrated with a glucose oxidation catalyst (GOx). Upon reaching cancer cells with the assistance of the aptamer, the nanoreactor underwent a structural collapse of the shell triggered by the high concentration of glutathione within cancer cells. This collapse led to the release of GOx and Dox, achieving targeted delivery and exhibiting significant efficacy in starving therapy. Additionally, the byproducts of glucose metabolism, gluconic acid and H2O2, enhanced the acidity and reactive oxygen species levels of the intracellular microenvironment, inducing oxidative damage to cancer cells. Simultaneously, released Dox acted as a potent broad-spectrum anticancer drug, inhibiting the activity of carnitine palmitoyltransferase 1A and exerting marked effects. Combining these effects ensures high anticancer efficiency, and the "dual-starvation" nanoreactor has the potential to establish a novel synergistic therapy paradigm with considerable clinical significance. Furthermore, this approach minimizes damage to normal organs, making it highly valuable in the field of cancer treatment.

The Anti-Diabetic Potential of Baicalin: Evidence from Rodent Studies

Baicalin is a biologically active flavonoid compound that benefits the organism in various pathological conditions. Rodent studies have shown that this compound effectively alleviates diabetes-related disturbances in models of type 1 and type 2 diabetes. Baicalin supplementation limited hyperglycemia and improved insulin sensitivity. The anti-diabetic effects of baicalin covered the main insulin-sensitive tissues, i.e., the skeletal muscle, the adipose tissue, and the liver. In the muscle tissue, baicalin limited lipid accumulation and improved glucose transport. Baicalin therapy was associated with diminished adipose tissue content and increased mitochondrial biogenesis. Hepatic lipid accumulation and glucose output were also decreased as a result of baicalin supplementation. The molecular mechanism of the anti-diabetic action of this compound is pleiotropic and is associated with changes in the expression/action of pivotal enzymes and signaling molecules. Baicalin positively affected, among others, the tissue insulin receptor, glucose transporter, AMP-activated protein kinase, protein kinase B, carnitine palmitoyltransferase, acetyl-CoA carboxylase, and fatty acid synthase. Moreover, this compound ameliorated diabetes-related oxidative and inflammatory stress and reduced epigenetic modifications. Importantly, baicalin supplementation at the effective doses did not induce any side effects. Results of rodent studies imply that baicalin may be tested as an anti-diabetic agent in humans.

The Cytotoxicity of Cotyledon orbiculata Aqueous Extract and the Biogenic Silver Nanoparticles Derived from the Extract

Green synthesized silver nanoparticles (AgNPs) have become popular because of their promising biological activities. However, for most of these nanoparticles, the cytotoxic effects have not been determined and their safety is not guaranteed. In a previous study, we successfully synthesized AgNPs (Cotyledon-AgNPs) using an extract of Cotyledon orbiculata, a medicinal plant traditionally used in South Africa to treat skin conditions. Cotyledon-AgNPs were shown to have significant antimicrobial and wound-healing activities. Fibroblast cells treated with extracts of C. orbiculata and Cotyledon-AgNPs demonstrated an enhanced growth rate, which is essential in wound healing. These nanoparticles therefore have promising wound-healing activities. However, the cytotoxicity of these nanoparticles is not known. In this study, the toxic effects of C. orbiculata extract and Cotyledon-AgNPs on the non-cancerous skin fibroblast (KMST-6) were determined using in vitro assays to assess oxidative stress and cell death. Both the C. orbiculata extract and the Cotyledon-AgNPs did not show any significant cytotoxic effects in these assays. Gene expression analysis was also used to assess the cytotoxic effects of Cotyledon-AgNPs at a molecular level. Of the eighty-four molecular toxicity genes analysed, only eight (FASN, SREBF1, CPT2, ASB1, HSPA1B, ABCC2, CASP9, and MKI67) were differentially expressed. These genes are mainly involved in fatty acid and mitochondrial energy metabolism. The results support the finding that Cotyledon-AgNPs have low cytotoxicity at the concentrations tested. The upregulation of genes such as FASN, SERBF1, and MKI-67 also support previous findings that Cotyledon-AgNPs can promote wound healing via cell growth and proliferation. It can therefore be concluded that Cotyledon-AgNPs are not toxic to skin fibroblast cells at the concentration that promotes wound healing. These nanoparticles could possibly be safely used for wound healing.

Effect of Pigmented Rice Consumption on Cardiometabolic Risk Factors: A Systematic Review of Randomized Controlled Trials

PURPOSE OF REVIEW

Dietary patterns that include polyphenols may help manage cardiometabolic risk factors. Pigmented rice contains phenolic acids and flavonoids that contribute to its antioxidant properties. This review examined the effect of polyphenol-containing pigmented rice on antioxidant status, lipid profile, glucose/insulin, blood pressure, and weight among adults. Four electronic databases including PubMed, ProQuest, EBSCOhost, and Google Scholar were systematically searched for relevant articles published in English since 2000, using PRISMA guidelines (PROSPERO registration: CRD42022358132). Two-staged screening resulted in the inclusion of seventeen (seven acute, ten chronic) randomized controlled trials. A random effects model was conducted on cardiometabolic outcomes reported in at least three studies.

RECENT FINDINGS

Acute intake increased plasma antioxidant activity and lowered postprandial glucose and insulin levels. Chronic consumption was associated with reductions in fasting glucose (WMD: -1.60 mg/dL; 95% CI:-3.05,-0.14, p = 0.03, k = 5, n = 349), weight (WMD: -0.23 kg, 95% CI: -0.44, -0.02, p = 0.03, k = 3, n = 182), and diastolic blood pressure (WMD: -1.39 mmHg, 95% CI: -2.21, -0.56, p = 0.001, k = 3, n = 185). No effect on total cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, body mass index, and systolic blood pressure was found. The consumption of pigmented rice may improve cardiometabolic risk factors. However, the small number of studies and differences in study design, including participants' health status, form of rice utilized, and duration of intervention, support the need for more high-quality trials to further investigate these findings.

The evolution of small molecule enzyme activators

There is a myriad of enzymes within the body responsible for maintaining homeostasis by providing the means to convert substrates to products as and when required. Physiological enzymes are tightly controlled by many signaling pathways and their products subsequently control other pathways. Traditionally, most drug discovery efforts focus on identifying enzyme inhibitors, due to upregulation being prevalent in many diseases and the existence of endogenous substrates that can be modified to afford inhibitor compounds. As enzyme downregulation and reduction of endogenous activators are observed in multiple diseases, the identification of small molecules with the ability to activate enzymes has recently entered the medicinal chemistry toolbox to afford chemical probes and potential therapeutics as an alternative means to intervene in diseases. In this review we highlight the progress made in the identification and advancement of non-kinase enzyme activators and their potential in treating various disease states.

L-carnitine reduces acute lung injury via mitochondria modulation and inflammation control in pulmonary macrophages

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a critical respiratory syndrome with limited effective interventions. Lung macrophages play a critical role in the pathogenesis of abnormal inflammatory response in the syndrome. Recently, impaired fatty acid oxidation (FAO), one of the key lipid metabolic signalings, was found to participate in the onset and development of various lung diseases, including ALI/ARDS. Lipid/fatty acid contents within mouse lungs were quantified using the Oil Red O staining. The protective effect of FAO activator L-carnitine (Lca, 50, 500, or 5 mg/mL) was evaluated by cell counting kit 8 (CCK-8) assay, real-time quantitative PCR (qPCR), ELISA, immunoblotting, fluorescence imaging, and fluorescence plate reader detection in lipopolysaccharide (LPS) (100 ng/mL)-stimulated THP-1-derived macrophages. The in vivo efficacy of Lca (300 mg/kg) was determined in a 10 mg/kg LPS-induced ALI mouse model. We found for the first time that lipid accumulation in pulmonary macrophages was significantly increased in a classical ALI murine model, which indicated disrupted FAO induced by LPS. Lca showed potent anti-inflammatory and antioxidative effects on THP-1 derived macrophages upon LPS stimulation. Mechanistically, Lca was able to maintain FAO, mitochondrial activity, and ameliorate mitochondrial dynamics. In the LPS-induced ALI mouse model, we further discovered that Lca inhibited neutrophilic inflammation and decreased diffuse damage, which might be due to the preservation of mitochondrial homeostasis. These results broadened our understanding of ALI/ARDS pathogenesis and provided a promising drug candidate for this syndrome.

Insights from a 30-year journey: function, regulation and therapeutic modulation of PD1

PD1 was originally discovered in 1992 as a molecule associated with activation-induced cell death in T cells. Over the past 30 years, it was found that PD1 has a critical role in avoiding overactivation-induced cell death and autoimmunity, whereas its inhibition unleashes anticancer immunity. Here, we outline the journey from the discovery of PD1 to its role as a breakthrough target in cancer immunotherapy. We describe its regulation and function and examine how a mechanistic understanding of PD1 signalling suggests a central function in setting the T cell activation threshold, thereby controlling T cell proliferation, differentiation, exhaustion and metabolic status. This threshold theory, in combination with new insights into T cell metabolism and a better understanding of immune cell modulation by the microbiota, can provide guidance for the development of efficient combination therapies. Moreover, we discuss the mechanisms underlying immune-related adverse events after PD1-targeted therapy and their possible treatment.

Tracheal microbiome and metabolome profiling in iatrogenic subglottic tracheal stenosis

BACKGROUND

To study the role of microecology and metabolism in iatrogenic tracheal injury and cicatricial stenosis, we investigated the tracheal microbiome and metabolome in patients with tracheal stenosis after endotracheal intubation.

METHODS

We collected 16 protected specimen brush (PSB) and 8 broncho-alveolar lavage (BAL) samples from 8 iatrogenic subglottic tracheal stenosis patients, including 8 PSB samples from tracheal scar sites, 8 PSB samples from scar-free sites and 8 BAL samples, by lavaging the subsegmental bronchi of the right-middle lobe. Metagenomic sequencing was performed to characterize the microbiome profiling of 16 PSB and 8 BAL samples. Untargeted metabolomics was performed in 6 PSB samples (3 from tracheal scar PSB and 3 from tracheal scar-free PSB) using high-performance liquid chromatography‒mass spectrometry (LC‒MS).

RESULTS

At the species level, the top four bacterial species were Neisseria subflava, Streptococcus oralis, Capnocytophaga gingivals, and Haemophilus aegyptius. The alpha and beta diversity among tracheal scar PSB, scar-free PSB and BAL samples were compared, and no significant differences were found. Untargeted metabolomics was performed in 6 PSB samples using LC‒MS, and only one statistically significant metabolite, carnitine, was identified. Pathway enrichment analysis of carnitine revealed significant enrichment in fatty acid oxidation.

CONCLUSION

Our study found that carnitine levels in tracheal scar tissue were significantly lower than those in scar-free tissue, which might be a new target for the prevention and treatment of iatrogenic tracheal stenosis in the future.

The Carnitine Palmitoyltransferase 1A Inhibitor Teglicar Shows Promising Antitumour Activity against Canine Mammary Cancer Cells by Inducing Apoptosis

Canine mammary tumours (CMTs) are the most common cancer in intact female dogs. In addition to surgery, additional targeted and non-targeted therapies may offer survival benefits to these patients. Therefore, exploring new treatments for CMT is a promising area in veterinary oncology. CMT cells have an altered lipid metabolism and use the oxidation of fatty acids for their energy needs. Here we investigated the tumoricidal effects of teglicar, a reversible inhibitor of carnitine palmitoyl transferase 1A (CPT1A), the rate-limiting enzyme for fatty acid import into mitochondria, on two CMT cells, P114 and CMT-U229. Viability and apoptosis were examined in CMT cells using the crystal violet assay, trypan blue assay, and flow cytometry analysis. The expression of mediators of apoptosis signalling (e.g., caspase-9, caspase-8, and caspase-3) was assessed by quantitative real-time polymerase chain reaction and western blot analyses. Teglicar was able to decrease cell viability and induce apoptosis in P114 and CMT-U229 cells. At the molecular level, the effect of teglicar was associated with an upregulation of the mRNA expression levels of caspase-9, caspase-8, and caspase-3 and an increase in their protein levels. In summary, our results show that teglicar has a potential effect against CMTs through the induction of apoptotic cell death, making it a promising therapeutic agent against CMTs.

Apolipoprotein A4 Elevates Sympathetic Activity and Thermogenesis in Male Mice

Long-chain fatty acids induce apolipoprotein A4 (APOA4) production in the small intestine and activate brown adipose tissue (BAT) thermogenesis. The increase in BAT thermogenesis enhances triglyceride clearance and insulin sensitivity. Acute administration of recombinant APOA4 protein elevates BAT thermogenesis in chow-fed mice. However, the physiological role of continuous infusion of recombinant APOA4 protein in regulating sympathetic activity, thermogenesis, and lipid and glucose metabolism in low-fat-diet (LFD)-fed mice remained elusive. The hypothesis of this study was that continuous infusion of mouse APOA4 protein would increase sympathetic activity and thermogenesis in BAT and subcutaneous inguinal white adipose tissue (IWAT), attenuate plasma lipid levels, and improve glucose tolerance. To test this hypothesis, sympathetic activity, BAT temperature, energy expenditure, body weight, fat mass, caloric intake, glucose tolerance, and levels of BAT and IWAT thermogenic and lipolytic proteins, plasma lipids, and markers of fatty acid oxidation in the liver in mice with APOA4 or saline treatment were measured. Plasma APOA4 levels were elevated, BAT temperature and thermogenesis were upregulated, and plasma triglyceride (TG) levels were reduced, while body weight, fat mass, caloric intake, energy expenditure, and plasma cholesterol and leptin levels were comparable between APOA4- and saline-treated mice. Additionally, APOA4 infusion stimulated sympathetic activity in BAT and liver but not in IWAT. APOA4-treated mice had greater fatty acid oxidation but less TG content in the liver than saline-treated mice had. Plasma insulin in APOA4-treated mice was lower than that in saline-treated mice after a glucose challenge. In conclusion, continuous infusion of mouse APOA4 protein stimulated sympathetic activity in BAT and the liver, elevated BAT thermogenesis and hepatic fatty acid oxidation, and consequently attenuated levels of plasma and hepatic TG and plasma insulin without altering caloric intake, body weight gain and fat mass.

Orchestral role of lipid metabolic reprogramming in T-cell malignancy

The immune function of normal T cells partially depends on the maneuvering of lipid metabolism through various stages and subsets. Interestingly, T-cell malignancies also reprogram their lipid metabolism to fulfill bioenergetic demand for rapid division. The rewiring of lipid metabolism in T-cell malignancies not only provides survival benefits but also contributes to their stemness, invasion, metastasis, and angiogenesis. Owing to distinctive lipid metabolic programming in T-cell cancer, quantitative, qualitative, and spatial enrichment of specific lipid molecules occur. The formation of lipid rafts rich in cholesterol confers physical strength and sustains survival signals. The accumulation of lipids through de novo synthesis and uptake of free lipids contribute to the bioenergetic reserve required for robust demand during migration and metastasis. Lipid storage in cells leads to the formation of specialized structures known as lipid droplets. The inimitable changes in fatty acid synthesis (FAS) and fatty acid oxidation (FAO) are in dynamic balance in T-cell malignancies. FAO fuels the molecular pumps causing chemoresistance, while FAS offers structural and signaling lipids for rapid division. Lipid metabolism in T-cell cancer provides molecules having immunosuppressive abilities. Moreover, the distinctive composition of membrane lipids has implications for immune evasion by malignant cells of T-cell origin. Lipid droplets and lipid rafts are contributors to maintaining hallmarks of cancer in malignancies of T cells. In preclinical settings, molecular targeting of lipid metabolism in T-cell cancer potentiates the antitumor immunity and chemotherapeutic response. Thus, the direct and adjunct benefit of lipid metabolic targeting is expected to improve the clinical management of T-cell malignancies.

Perhexiline: Old Drug, New Tricks? A Summary of Its Anti-Cancer Effects

Cancer metabolic plasticity, including changes in fatty acid metabolism utilisation, is now widely appreciated as a key driver for cancer cell growth, survival and malignancy. Hence, cancer metabolic pathways have been the focus of much recent drug development. Perhexiline is a prophylactic antianginal drug known to act by inhibiting carnitine palmitoyltransferase 1 (CPT1) and 2 (CPT2), mitochondrial enzymes critical for fatty acid metabolism. In this review, we discuss the growing evidence that perhexiline has potent anti-cancer properties when tested as a monotherapy or in combination with traditional chemotherapeutics. We review the CPT1/2 dependent and independent mechanisms of its anti-cancer activities. Finally, we speculate on the clinical feasibility and utility of repurposing perhexiline as an anti-cancer agent, its limitations including known side effects and its potential added benefit of limiting cardiotoxicity induced by other chemotherapeutics.

The Association of Circulating L-Carnitine, γ-Butyrobetaine and Trimethylamine N-Oxide Levels with Gastric Cancer

Our study aimed to evaluate the association between gastric cancer (GC) and higher concentrations of the metabolites L-carnitine, γ-butyrobetaine (GBB) and gut microbiota-mediated trimethylamine N-oxide (TMAO) in the circulation. There is evidence suggesting that higher levels of TMAO and its precursors in blood can be indicative of either a higher risk of malignancy or indeed its presence; however, GC has not been studied in this regard until now. Our study included 83 controls without high-risk stomach lesions and 105 GC cases. Blood serum L-carnitine, GBB and TMAO levels were measured by ultra-high-performance liquid chromatography–mass spectrometry (UPLC/MS/MS). Although there were no significant differences between female control and GC groups, we found a significant difference in circulating levels of metabolites between the male control group and the male GC group, with median levels of L-carnitine reaching 30.22 (25.78–37.57) nmol/mL vs. 37.38 (32.73–42.61) nmol/mL (p < 0.001), GBB–0.79 (0.73–0.97) nmol/mL vs. 0.97 (0.78–1.16) nmol/mL (p < 0.05) and TMAO–2.49 (2.00–2.97) nmol/mL vs. 3.12 (2.08–5.83) nmol/mL (p < 0.05). Thus, our study demonstrated the association between higher blood levels of L-carnitine, GBB, TMAO and GC in males, but not in females. Furthermore, correlations of any two investigated metabolites were stronger in the GC groups of both genders in comparison to the control groups. Our findings reveal the potential role of L-carnitine, GBB and TMAO in GC and suggest metabolic differences between genders. In addition, the logistic regression analysis revealed that the only significant factor in terms of predicting whether the patient belonged to the control or to the GC group was the blood level of L-carnitine in males only. Hence, carnitine might be important as a biomarker or a risk factor for GC, especially in males.

Unravelling the role of obesity and lipids during tumor progression

The dysregulation of the biochemical pathways in cancer promotes oncogenic transformations and metastatic potential. Recent studies have shed light on how obesity and altered lipid metabolism could be the driving force for tumor progression. Here, in this review, we focus on liver cancer and discuss how obesity and lipid-driven metabolic reprogramming affect tumor, immune, and stroma cells in the tumor microenvironment and, in turn, how alterations in these cells synergize to influence and contribute to tumor growth and dissemination. With increasing evidence on how obesity exacerbates inflammation and immune tolerance, we also touch upon the impact of obesity and altered lipid metabolism on tumor immune escape.

Fatty acid metabolism: A new therapeutic target for cervical cancer

Cervical cancer (CC) is one of the most common malignancies in women. Cancer cells can use metabolic reprogramming to produce macromolecules and ATP needed to sustain cell growth, division and survival. Recent evidence suggests that fatty acid metabolism and its related lipid metabolic pathways are closely related to the malignant progression of CC. In particular, it involves the synthesis, uptake, activation, oxidation, and transport of fatty acids. Similarly, more and more attention has been paid to the effects of intracellular lipolysis, transcriptional regulatory factors, other lipid metabolic pathways and diet on CC. This study reviews the latest evidence of the link between fatty acid metabolism and CC; it not only reveals its core mechanism but also discusses promising targeted drugs for fatty acid metabolism. This study on the complex relationship between carcinogenic signals and fatty acid metabolism suggests that fatty acid metabolism will become a new therapeutic target in CC.

The Potential Inhibitory Role of Acetyl-L-Carnitine on Proliferation, Migration, and Gene Expression in HepG2 and HT29 Human Adenocarcinoma Cell Lines

Malignancies of the liver and colon are the most prevalent forms of digestive system cancer globally. Chemotherapy, one of the most significant treatments, has severe side effects. Chemoprevention using natural or synthetic medications can potentially reduce cancer severity. Acetyl-L-carnitine (ALC) is an acetylated derivative of carnitine essential for intermediate metabolism in most tissues. This study aimed to investigate the effects of ALC on the proliferation, migration, and gene expression of human liver (HepG2) and colorectal (HT29) adenocarcinoma cell lines. The cell viability and half maximal inhibitory concentration of both cancer cell lines were determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Wound healing after treatment was assessed using a migration assay. Morphological changes were imaged using brightfield and fluorescence microscopy. Post treatment, apoptotic DNA was detected using a DNA fragmentation assay. The relative mRNA expressions of matrix metallopeptidase 9 (MMP9) and vascular endothelial growth factor (VEGF) were evaluated using RT-PCR. The results showed that ALC treatment affects the wound-healing ability of HepG2 and HT29 cell lines. Changes in nuclear morphology were detected under fluorescent microscopy. ALC also downregulates the expression levels of MMP9 and VEGF in HepG2 and HT29 cell lines. Our results indicate that the anticancer action of ALC is likely mediated by a decrease in adhesion, migration, and invasion.

Estrogen receptor alpha signaling in dendritic cells modulates autoimmune disease phenotype in mice

Estrogen is a disease-modifying factor in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) via estrogen receptor alpha (ERα). However, the mechanisms by which ERα signaling contributes to changes in disease pathogenesis have not been completely elucidated. Here, we demonstrate that ERα deletion in dendritic cells (DCs) of mice induces severe neurodegeneration in the central nervous system in a mouse EAE model and resistance to interferon beta (IFNβ), a first-line MS treatment. Estrogen synthesized by extragonadal sources is crucial for controlling disease phenotypes. Mechanistically, activated ERα directly interacts with TRAF3, a TLR4 downstream signaling molecule, to degrade TRAF3 via ubiquitination, resulting in reduced IRF3 nuclear translocation and transcription of membrane lymphotoxin (mLT) and IFNβ components. Diminished ERα signaling in DCs generates neurotoxic effector CD4+ T cells via mLT-lymphotoxin beta receptor (LTβR) signaling. Lymphotoxin beta receptor antagonist abolished EAE disease symptoms in the DC-specific ERα-deficient mice. These findings indicate that estrogen derived from extragonadal sources, such as lymph nodes, controls TRAF3-mediated cytokine production in DCs to modulate the EAE disease phenotype.

Repair of airway epithelia requires metabolic rewiring towards fatty acid oxidation

Epithelial tissues provide front-line barriers shielding the organism from invading pathogens and harmful substances. In the airway epithelium, the combined action of multiciliated and secretory cells sustains the mucociliary escalator required for clearance of microbes and particles from the airways. Defects in components of mucociliary clearance or barrier integrity are associated with recurring infections and chronic inflammation. The timely and balanced differentiation of basal cells into mature epithelial cell subsets is therefore tightly controlled. While different growth factors regulating progenitor cell proliferation have been described, little is known about the role of metabolism in these regenerative processes. Here we show that basal cell differentiation correlates with a shift in cellular metabolism from glycolysis to fatty acid oxidation (FAO). We demonstrate both in vitro and in vivo that pharmacological and genetic impairment of FAO blocks the development of fully differentiated airway epithelial cells, compromising the repair of airway epithelia. Mechanistically, FAO links to the hexosamine biosynthesis pathway to support protein glycosylation in airway epithelial cells. Our findings unveil the metabolic network underpinning the differentiation of airway epithelia and identify novel targets for intervention to promote lung repair.

Anti-obesity potential of heat-killed Lactiplantibacillus plantarum K8 in 3T3-L1 cells and high-fat diet mice

Probiotics exert anti-obesity effects in high-fat diet (HFD) obese mice, but there are few studies on anti-obesity using heat-killed probiotics. Here, we investigated the effect of heat-killed Lactiplantibacillus plantarum K8 (K8HK) on the anti-differentiation of 3T3-L1 preadipocytes and on anti-obesity in HFD mice. K8HK decreased triglyceride (TG) accumulation in 3T3-L1 cells. Specifically, 1 × 10⁹ CFU/mL K8HK showed the greatest anti-obesity effect, while the same concentration of live L. plantarum K8 (K8 Live) showed cytotoxicity. K8HK increased suppressor of cytokine signaling (SOCS)-1, which might affect the JAK2-STAT3 signaling pathway activated during differentiation. As a result, the levels of transcription factors of adipogenesis such as Peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) decreased in K8HK-treated cells. We also observed a decrease in the lipogenic enzymes and fatty acid binding protein 4 (FABP4). In the mouse study, oral ingestion of K8 Live and K8HK showed weight reduction and decrease in blood TG content at 12 weeks of feeding. In addition, TG synthesis was suppressed in liver and adipose tissues, and genes related to fat metabolism were suppressed. This study suggests that K8HK could be a good material to prevent obesity by inhibiting adipogenesis genes related to fat metabolism.